Oxy-fuel burner for reducing the level of operating noise

ABSTRACT

A metallurgical burner of the type having a nozzle end for producing a flame by combustion of fuel and an oxidizing fluid. The burner is characterized in that the nozzle contains a plurality of mixing cups surrounding and projecting beyond a plurality of pairs of fuel and oxidizing fluid discharge ports. The mixing cups are sized so that combustion takes place inside or at the mouth of each cup thereby reducing the operating noise level of the burner. Further features of the burner include fluid cooling and quick change capability for nozzle end replacement.

0 United States Patent 1151 3,680,785 Miller 1 1 Aug. 1, 1972 [54]OXY-FUEL BURNER FOR REDUCING 3,202,201 8/1965 Masella et al ..239/132.3THE LEVEL OF OPERATING NOISE 2,433,610 12/1947 Hughey ..239/l 32.3 [72]lnventorz Keith A. Miller, Allentown, Pa. Primary EXaminer M Henson woodJr. [73] Assignee: Air Productsand Chemicals, Inc., AssistantExaminer-John J. Love Allentown, Pa. Attorney-Ronald B. Sherer, James C.Simmons and 221 Filed: June 29, 1970 Kiev [21] Appl. No.: 50,442 [57]ABSTRACT A metallurgical burner of the type having a nozzle end 52 us.c1 ..239/132.3, 239/433 for producing a flame by combustion of fuel andn 51 1111. C1. .3051, 15/00 oxidizing fluid- The burner is Characterizedin that the 58 Field of Search .239/132, 132.1, 132.3, 433 nozzlecontains a plurality of mixing P surrounding and projecting beyond aplurality of pairs of fuel and [56] References Cited oxidizing fluiddischarge ports. The mixing cups are sized so that combustion takesplace inside or at the UNITED STATES PATENTS mouth of each cup therebyreducing the operating noise level of the burner. Further features ofthe 3,198,436 KLll'ZlnSkl t 3i. burner include cooling and quick changep 3,1 18,608 1/1964 Berry ..239/132.3 bility for nozzle end repiacement2,861,628 11/1958 Fraser ..239/132.3 X 3,043,577 7/1962 Berry.;.239/l32.3 6 Claims, 5 Drawing Figures PATENTEDAuc 1 I972} 3,680,785

sum 1 or 2 FIG. 2.

FIG I KEITH AMILLER INVENTOR AT TORNEY PATENTED 1197? 3.680.785

SiIIiET 2 BF 2 FIG. 3.

FIG. 5. FIG. 4.

KEITH A. MILLER INVENTOR.

ATTORNL Y BACKGROUND OF THE INVENTION This invention pertains to ametallurgical burner of the type used in melting vessels for meltingprimary metals. Such burners are commonly employed to melt large volumesof metallurgical scrap that is to be subsequently refined. The burnersare normally placed in the wall or the roof of the furnace and employ anoxyfuel mixture that is combusted and directed at the metals beingmelted.

A burner of this type is shown in US. Pat. No. 3,1 18,608. Theaforementioned patent shows a plurality of individual pairs of fuel andoxygen conduits that terminate at the bottom surface of a slottedaperture on the outer surface of the burner nozzle. The burner nozzle inthe outward end thereof contains a plurality of these slots where thepairs of oxygen and fuel conduits supply a mixture to the surface of theburner nozzle. In a burner of this type, combustion generally takesplace forward of the outermost surface of the burner nozzle. Thisresults in a high operating noise level. Such a high operating noiselevel is disturbing to the human ear and in certain instances has causedloss of human hearing.

SUMMARY OF THE INVENTION The present invention relates to ametallurgical burner that can produce melting temperatures for primarymetal refining vessels using a fuel and oxidizing fluid mixture- Theburner of the present invention is fluid cooled and is provided with aplurality of mixing cups on the outward end of the burner nozzle tosignificantly decrease the operating noise level of such a burner. Themixing cups insure that combustion takes place at the mouth of each cupor inwardly thereof so that the flame front never leaves the face of theburner. The vburner of the present invention is readily fabricated andcan be made in two sections with a quick change capability so that thenozzle end can be easily replaced. 1

Therefore, it is the primary object of this invention to provide animproved metallurgical burner.

It is a further object of this invention to provide a metallurgicalburner for primary melting that operates at significantly reduced noiselevels.

It is still another object of this invention to provide a metallurgicalburner of the oxy-fuel type that is fluid cooled so that it can surviveits operating environment.

It is still a further object of this invention to provide ametallurgical burner of the oxy-fuel type that is fluid cooled and thatcan be quickly disassembled to replace the nozzle end thereof.

BRIEF DESCRIPTION OF THE DRAWING DETAILED DESCRIPTION OF THE PREFERREDEMBODIMENT Referring to FIG. 1 there is shown a metallurgical burner 10.The burner is preferably fabricated with a two-piece housing 12 and 14.The housing sections 12-14 are secured together by a quick disconnectcoupling 16 such as manufactured under the tradename VICTAULIC by theVictaulic Company of America. Such couplings 16 are well known to theindustry and sealed by a pair of circumferential grooves 18 and 20disposed in the housing sections of 12-14. As an integral part of thecoupling there is a gasket or sealing member 22 to prevent fluid leaksfrom the burner.

The upper section 14 of burner 10 has a cap 24 affixed thereto as bycircumferential weld 26. The cap 24 contains a central opening 28 forreceiving a longitudinal conduit 30 of housing section 12. A pluralityof recesses on surface 28 contain a corresponding number of O-ring typesealing members 32 to insure fluidtight sealing of the cap 24 to theconduit 30. It is preferable that at least three sealing members 32 beused so that there is in effect two pressure seals in each direction.Mounted on top of cap 24 is a conduit 36 which also contains an end cap34. Disposed on the end cap 34 is a fluid conduit 38 that communicateswith a central aperture 40 in cap 34. The aperture 40 in'cap 34 containsan O-ring sealing member 42 to assure a fluid-type seal between cap 34and central fluid conduit 44. The central fluid conduit 44 projects intoconduit 38 for receiving a fluid coolant from a source not shown.

Conduit 36 contains a suitable coupling 46 for receipt of a fluidconduit not shown. Coupling 46 can be a flange welded to conduit 36 andcommunicating with aperture 48 in conduit 36 for conducting a suitableoxidizing fluid into the inner area 50 defined by conduit 36 and conduit44 and then into he interior area 52 defined by conduit 30 and conduit44 and into the nozzle of the burner as will hereinafter be more fullydescribed.

The lower housing 12 of the burner 10 has affixed to its lower end anozzle shown generally as 54. The nozzle 54 contains a plurality ofgenerally cylindrical mixcan be conducted from conduit 38 throughconduit 44 FIG. 1 is a fragmentary section taken along lines l-- tochamber 60 radially outwardly of the nozzle through passages 58 and thento passage 62 defined by the interior wall of housing 12 and theexterior wall of an inner sleeve 64 that is affixed to the nozzle 54 asby circumferential weld 66. The fluid is then conducted outwardly of theburner through aperture 68 in housing 12 by means of a coupling 70affixed to the housing, the coupling receiving a fluid conduit such as ahose.

The sleeve 64 in communication with conduit 30 defines an annularpassage that communicates with an aperture 72 in housing 14. Theaperture 72 has connected thereto in fluid tight engagement therewithconduit coupling 74 for receipt of a fuel such as natural gas. The fuelpath, from coupling 74 through aperture 72 between sleeve 64 and conduit30 to he nozzle 54 is isolated from the fluid path by a suitablecircumferential sealing member 76 which is mounted on the interior wallof housing 14. Between the outer wall of sleeve 64 and sealing member 76is an O-ring seal 78 so that the burner sections can be sealed influidtight arrangement, yet can be readily separated.

The mixing cups 56 project inwardly from the outer surface 80 of noule54 and terminate at a generally flat surface 82. Communicating withsurface 82 are circumferential grooves 84 and 86 (FIG. 3) which in turncommunicate with the passages defined by the sleeve 64 and conduit 30and passage 52 (defined by conduits 30,40) respectively in the burner.As is shown in Figure the grooves 84 and 86 are machined in the nozzlebody so that as the fuel and oxidizing fluid streams leave the bottomface 82 of cup 56 they are caused to impinge upon one another within thecup 56. This assures mixing of the fuel and oxidizing fluid. Moreimportantly it is believed that the impinging streams create a negativepartial pressure (relative to the burner environment) at the bottom face82 of cup 56 so that the flame front is retained at the mouth 88 of cup56.

In operation conduit 38 is connected to a source of suitable fluidcoolant such as water. Coupling 70 is connected to a hose or otherdevice for removing the fluid coolant and disposing thereof or causingthe same to be cooled and recirculated. Coupling 74 is connected by asuitable conduit such as a hose to a source of fuel such as natural gas.Coupling 46 is connected to a source of an oxidizing fluid such asoxygen by a suitable conduit. The burner can then be lowered partiallyinto a melting furnace and survive its environment because it is fluidcooled. The oxygen and fuel are introduced into the mixing cups 56 wherethey are intimately mixed and combustion results at the mouth 88 of thecups or inwardly thereof. With combustion at this point the operatingnoise level is significantly reduced because the flame front has notbeen allowed to separate from the outer surface of the nozzle.Maintaining the flame front in this position significantly reduces thenoise level because the flame front has no aerial path between it andthe face of the burner nozzle. The following table sets forth tests ofburners of this type with and without mixing cup, wherein sound levelswere recorded when the burner was fired into the open air.

TABLE Firing Rate Noise Level (Decibels) (Millions of BTU/Hr) WithMixing Cups Without Mixing Cups 4 96 5 I08 6 l l5 10 l 19 l23 14 124 I5l28 l6 l25 126 130 127 131 Examination of the foregoing table shows thatfor the burner with mixing cups the measured noise level issignificantly lower. it is well known that at the 100 decibel level areduction of 4 decibels is significant.

It has also been found from examination of the various data generatedthat the length to diameter ratio of the fuel gas passages must beextremely large. However, maintaining the ratio relationship of themixing cup length to diameter will still assure a significant reductionin the noise level.

There is shown in FIG. 4 an end view of a nozzle according to thepresent invention wherein the fuel and oxygen passages are discreteconduits and 92, 93 respectively instead of grooves as shown withrespect to the embodiment of FIG. 1. In this embodiment, the noule isconstructed so that conduit 90 communicates with the source of oxygen ashas been described with respect to FIG. 1 and the fuel passages 92,93communicate with the source of fuel as described in connection with theembodiment of FIG. 1. The nozzle of F IG. 4 is cooled in the same manneras is the nozzle of F 1G. 1 and to that end contains a central chamber94 and radial passages 96 for conducting the fluid between the mixingcups and then to the inner wall of the housing of the burner and thenoutwardly thereof.

Having thus described my invention, the appended claims define what isdesired to be secured by Letters Patent of the United States.

IClaim:

1. In a burner of the oxy-fuel type comprising a generally elongatedhousing with internal fluid cooling passages and internal fuel andoxidizing gas passages to produce and direct a flame at a nozzle endthereof, the improvement which comprises:

a nozzle containing a plurality of mixing cups extending inwardly fromthe outer surface of said nozzle and communicating with an internalrelatively flat surface disposed normal to the longitudinal axis of thecup, containing a fuel aperture and an oxidizing fluid aperture, wherebysaid cups cause intimate mixing of the fuel and oxidizing fluid thereinand help retain the flame front at or inwardly of the mouth of the cupsto reduce the operating noise level of said burner, each of said cupshaving a length to diameter ratio of between 0.4 to 1.4;

the fuel and oxidizing fluid passages communicating with the respectivefuel and fluid passages of said burner; and

means for cooling the nozzle with the cooling fluid used in the burnerhousing.

2. A burner according to claim 1 wherein the ratio of thecross-sectional area of oxidizing fluid passage to the cross-sectionalarea of the fuel passage is between 0.5 and 1.3.

3. A burner according to claim 2 wherein the cooling fluid enters thecenter of the nozzle and is conducted through a plurality of passagesacross the face of the nozzle to the sides thereof where it is directedinto the housing for removal from the burner.

4. A burner according to claim 3 wherein the housing is made influidtight removable sections for easy replacement of the burner nozzle.

5. A metallurgical burner of the oxy-fuel type comprising incombination:

a generally cylindrical housing having a cover on one end and a nozzleon the other end;

the nozzle containing a plurality of mixing cups extending inwardly fromthe outer surface of said nozzle and communicating with an internal flatsurface disposed normal to the longitudinal axis of the cup containing afuel aperture and an oxidizing passages communicating with the fuel gaspassage in the nozzle and another of the passages communicating with theoxidizing passage in the nozzle; means in the housing for introducingthe fuel and oxidizing gas to the respective conduits and means in thehousing for introducing and removing the coolthe housing having aplurality of internal passages for receiving cooling fluid, fuel and anoxidizing gas, the cooling fluid passages so constructed and arranged tointroduce cooling fluid down the center 10 of the burner and up alongthe walls of the housing 6. A burner according to claim 5 wherein theinward surface of each of said mixing cups contains at least oneoxidizing fluid aperture and a plurality of fuel apertures.

and then outwardly of said housing, one of the 353 IUNETED STATES PATENTe ,52m ra CERTEFIATE UF QQRREUHQN Patent N 3,680, 785 Dated August 1,1972 Inventofls) K. A. Miller It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

T is

In the drawings Sheet 1, Figure l, the reference numeral 78 at theright-hand side of the Figure below the lower section arrow of sectionline 3-3 should be numeral 86.

Signed and sealed this 10thday of April 1973.

(SEAL) Attest:

-EDWARD M.PLET( IHER,JR. ROBERT GOTTSCHALK Attestlng OfficerCommissioner of Patents

1. In a burner of the oxy-fuel type comprising a generally elongated housing with internal fluid cooling passages and internal fuel and oxidizing gas passages to produce and direct a flame at a nozzle end thereof, the improvement which comprises: a nozzle containing a plurality of mixing cups extending inwardly from the outer surface of said nozzle and communicating with an internal relatively flat surface disposed normal to the longitudinal axis of the cup, containing a fuel aperture and an oxidizing fluid aperture, whereby said cups cause intimate mixing of the fuel and oxidizing fluid therein and help retain the flame front at or inwardly of the mouth of the cups to reduce the operating noise level of said burner, each of said cups having a length to diameter ratio of between 0.4 to 1.4; the fuel and oxidizing fluid passages communicating with the respective fuel and fluid passages of said burner; and means for cooling the nozzle with the cooling fluid used in the burner housing.
 2. A burner according to claim 1 wherein the ratio of the cross-sectional area of oxidizing fluid passage to the cross-sectional area of the fuel passage is between 0.5 and 1.3.
 3. A burner according to claim 2 wherein the cooling fluid enters the center of the nozzle and is conducted through a plurality of passages across the face of the nozzle to the sides thereof where it is directed into the housing for removal from the burner.
 4. A burner according to claim 3 wherein the housing is made in fluidtight removable sections for easy replacement of the burner nozzle.
 5. A metallurgical burner of the oxy-fuel type comprising in combination: a generally cylindrical housing having a cover on one end and a nozzle on the other end; the nozzle containing a plurality of mixing cups extending inwardly from the outer surface of said nozzle and communicating with an internal flat surface disposed normal to the longitudinal axis of the cup containing a fuel aperture and an oxidizing gas aperture; and passages for circulating a cooling fluid throughout the nozzle, each of said cups having a length to diameter ratio of between 0.4 and 1.4, and the ratio of cross-sectional area of the oxidizing gas aperture to the cross-sectional area of the fuel aperture is between 0.5 and 1.3; the housing having a plurality of internal passages for receiving cooling fluid, fuel and an oxidizing gas, the cooling fluid passages so constructed and arranged to introduce cooling fluid down the center of the burner and up along the walls of the housing and then outwardly of said housing, one of the passages communicating with the fuel gas passage in the nozzle and another of the passages communicating with the oxidizing passage in the nozzle; means in the housing for introducing the fuel and oxidizing gas to the respective conduits and means in the housing for introducing and removing the cooling fluid.
 6. A burner according to claim 5 wherein the inward surface of each of said mixing cups contains at least one oxidizing fluid aperture and a plurality of fuel apertures. 